N-N&#39;-dialkylphenylenediamines as curing agents in polyurethane and polyurea manufacture by reaction injection molding

ABSTRACT

N,N&#39;-dialkyl- and diaylphenylenediamines are effective curing agents in combination with other polyamines and polyols in reaction injection molding for a diverse class of polyisocyanates. The diamines provide a broad spectrum of cure times, as well as giving elastomers an interesting and useful diversity of properties. Such polyamines may be used as a constituent in a blend of polyamines as the isocyanate-reactive component, in which case the elastomer may be viewed as predominantly a polyurea, or as a constituent in a blend with polyols, in which case the elastomer may be viewed as an elastomer with both urethane and urea segments.

BACKGROUND OF THE INVENTION

As a subclass of commercially available polymers, polyurethaneelastomers have several properties whose advantages confer uniquebenefits on these products. Typically, polyurethanes show high abrasionresistance with high load bearing, excellent cut and tear resistance,high hardness, resistance to ozone degradation, yet are pourable andcastable. Compared to metals, polyurethanes are lighter in weight, lessnoisy in use, show better wear and excellent corrosion resistance whilebeing capable of less expensive fabrication. Compared to other plastics,polyurethanes are non-brittle, much more resistant to abrasion, andexhibit good elastomeric memory. Polyurethanes find use in such diverseproducts as aircraft hitches, bushings, cams, gaskets, gravure rolls,star wheels, washers, scraper blades, impellers, gears, and drivewheels.

Part of the utility of polyurethanes derives from their enormousdiversity of properties resulting from a relatively limited number ofreactants. Typically, polyurethanes are prepared on site by curingurethane prepolymers, which are adducts of polyisocyanates andpolyhydric alcohols. A large class of such prepolymers are approximately2:1 adducts of a diisocyanate, OCN--Y--NCO, and a diol, HO--Z--OH, whoseresulting structure is OCN--Y--NHCO₂ --Z--O₂ CNH--Y--NCO. Although Y issusceptible of great variety, usually being a divalent alkyl,cyclohexyl, or aromatic radical, in fact the most available prepolymersare made from toluene diisocyanate (TDI), most readily available as amixture of 2,4- and 2,6-isomers which is rich in the former isomer, ormethylene-4,4'-diphenyldiisocyanate (MDI). The diols used display agreater range of variety; Z may be a divalent alkyl radical (i.e., analkylene group), and the diols frequently are ethers or esters which arethe condensation products of glycols with alkylene oxides ordicarboxylic acids, resp.

The polyurethane elastomers are formed by curing the prepolymer. Curingis the reaction of the terminal isocyanate groups of the prepolymer withactive hydrogens of a polyfunctional compound so as to form highpolymers through chain extension and, in some cases, crosslinking.Diols, especially alkylene diols, are the most common curing agents forMDI-based prepolymers, and representing such diols with the structureHO--X--OH, where X is an organic moiety, most usually an alkylene group,the resulting polymer has as its repeating unit,

    (--Y--NHCO.sub.2 ZO.sub.2 CNH--Y--NHCO.sub.2 --X--O--CONH--).

Where a triol or a higher polyhydric alcohol is used crosslinking occursto afford a nonlinear polymer.

Although other polyfunctional chemicals, especially diamines, aretheoretically suitable, with but a few exceptions none have achievedcommercial importance as a curing agent. The major exception is4,4'-methylene-di-ortho-chloroaniline, usually referred to as MOCA, acuring agent which is both a chain extender and a crosslinker. TDI-basedprepolymers typically are cured with MOCA, and the resulting productsaccount for perhaps most of the polyurethane elastomer market. Onereason that polyhydric alcohols generally have gained acceptance ascuring agents is that their reaction with urethane prepolymers issufficiently fast to be convenient, but not so fast as to make itdifficult to work with the resulting polymer. In casting polymers it isdesirable that the set-up time be reasonably short, yet long enough forthe material to be cast into molds. This property is conventionallyreferred to as pot life. Generally speaking, diamines react withprepolymers, and especially MDI-based prepolymers, so quickly that theyare not usable as curing agents. However, primary aromatic diamines withelectronegative groups on the aromatic ring, or with alkyl groups orthoto the amino moiety, exhibit sufficiently decreased reactivities withsome prepolymers as to afford a desirable pot life, hence the use of,for example, MOCA as a curing agent for TDI-based prepolymers. However,MOCA and others of the aforementioned diamines still remain too reactiveto be used, for example, with MDI-based prepolymers.

On the other hand, the advent of reaction injection molding (RIM)provides a means of processing polyurethanes which is well adapted to ashort pot life. Reaction injection molding is a process that allowspolymerization and crosslinking to take place simultaneous with formingof a part into its final shape. Because of the rapid curing ofpolyurethanes, compatible with the fast cycle times of RIM, thesepolymers seem exceptionally well suited to RIM processing althoughepoxies, nylons, and even polyesters have been made by the RIM process.

In RIM, two highly reactive streams of chemicals are brought togetherunder high pressure in a small mixing chamber where the streams areimpingement mixed by being sprayed directly into each other beforeentering the mold. The mixed material flows directly into a mold at0.35-0.7 MPa (50-100 psi), a low pressure compared to that used instandard injection molding, where the chemical reaction is completed andthe part cures. One of the ingredient streams (the first stream)contains the isocyanate and the other stream (the second stream)contains components having isocyanate-reactive hydrogens, such aspolyols and amines, and other components as catalysts, pigments, blowingagents, and surfactants. Much of the technology is currently used in theautomotive industry to produce parts such as bumper covers and fenders.Parts are produced on a cycle of 3 minutes or less, and large urethaneparts have been successfully demolded in 30 seconds or less afterinjection.

We have found that a large class of alkylated aromatic polyamines areexcellent isocyanate-reactive components, or curing agents, forpolyisocyanates in the preparation of RIM elastomers. Among theadvantages of the curing agents of this invention are that the resultingelastomers can be expected to show excellent compression set, to havequite high tensile strength, and to show greater elongation andincreased impact properties. The resulting elastomers are thermoplasticor thermosetting polymers, depending on whether or not a crosslinkingagent has been added, or if any of the other components present act ascrosslinking agents. Additionally, the curing agents themselves for themost part are liquids at room temperature, facilitating their use at RIMtemperature. The curing agents may be used for both TDI and MDI-basedpolyisocyanates, which give rise to the two largest classes ofpolyurethane and polyurea elastomers. In short, the unique properties ofboth the curing agents and the resulting elastomers make each veryhighly desirable in RIM formulations.

The curing agents of this invention are secondary aromatic diamines,which as a class formerly were not considered as acceptable curingagents for polyurethane and polyurea elastomers. U.S. Pat. No. 3,846,351describes the quite narrow use of the N,N'-dialkylphenylenediamines usedin our invention in combination with polyols as catalysts and chainextenders in the non-RIM production of flexible polyurethane foams. Itis important to recognize that such secondary diamines were taught to beused only in combination with polyols, preferably at the relatively lowlevel of 0.5-5 parts per 100 parts of polyol. In U.S. Pat. No. 3,711,571the patentee cites di-sec-butyl-p-phenylenediamine as the sole exampleof a disecondary amine used as a chain extender for typical urethaneprepolymers. Mixtures of aromatic primary diamines and aromaticsecondary diamines to cure urethane prepolymers were disclosed in U.S.Pat. No. 3,194,793 where the patentee taught that the secondary diaminescould not constitute more than 75% of the diamine mixture withoutdeleterious consequences. In an examination of aromatic diamines aschain extenders in polyurethane elastomers by reaction injectionmolding, the sole secondary aromatic diamine examined,N,N'-diisopropyl-4,4'-methylenedianiline, afforded products whoseproperties were generally unacceptably inferior to those exhibited bypolyurethanes made with primary aromatic diamines as curing agents. "D.Nissen and R. A. Markovs," Proceedings of the 27th SPI AnnualTechnical/Marketing conference, 71-8. More recently we have shown inU.S. Pat. No. 4,578,446 that contrary to the prior conventional wisdomalkylated methylenedianilines are suitable curing agents for urethaneprepolymers, i.e., in elastomer production via non-RIM processes.

To aid in exposition the isocyanate-reactive components can beclassified as either polyols (polyhydric alcohols) or polyamines. Eachof these classes has two functionally defined subclasses; backbonepolyols (or polyamines) and chain extender polyols (or polyamines). Thedifference is that, e.g., the backbone polyol reacts with theisocyanates in the first stream to afford short polymeric segments, andthe chain extender polyamine links the short segments to form longerchains. The diamines of this invention act as chain extender polyamines.

The RIM elastomers which can be made from the amines of this inventionare diverse and depend upon the nature of the isocyanate-reactivestream. In one variant the second stream as the isocyanate-reactivecomponent is a mixture of backbone and chain extender polyamines. Thatis, the second stream may have catalysts, pigments, surfactants, etc.,but contain little, if any, isocyanate-reactive components other thanthe polyamines. In this variant the elastomer is exclusively, or almostso, a polyurea.

In another variant the second stream has as the isocyanate-reactivecomponent a mixture of the diamines of this invention, which act aschain extender amines, and various backbone polyols. The mixture willgenerally have from about 20 to about 80% of amine, on an equivalentsbasis, and more usually contains 30-70 equivalents percent of amine. (Anequivalent of polyamine or polyol is an amount which furnishes as manyamino or hydroxyl groups as there are isocyanate groups in the firststream. As used herein, "equivalents percent" refers to the percentageof amine and/or polyol equivalents relative to isocyanate equivalents.)

In each of the foregoing variants a portion of the chain-extenderdiamines of this invention may be replaced by a chain extender polyol ora second chain extender polyamine. Although this will be described morefully within, to exemplify one of these subvariants the second streammay contain a backbone polyamine, the chain extender diamines of thisinvention, and a chain extender polyol where the polyol level is roughly20-100 equivalents percent of the chain extender diamine.

SUMMARY OF THE INVENTION

The object of this invention is to prepare polyurethane and polyureaelastomers by reaction injection molding using N,N'-dialkyl- ordiarylphenylenediamines as curing agents. In an embodiment the curingagent is an alkylated diamine where the alkyl group contains up to about20 carbon atoms. In another embodiment the amine is anN,N'-dialkyl-p-phenylenediamine. Other objects and embodiments willbecome obvious from the description which follows.

DESCRIPTION OF THE INVENTION

In one aspect the invention herein is a reaction injection moldedelastomer made by reacting a polyisocyanate and a mixture ofisocyanate-reactive material having one or more diamines of thisinvention as a chain extender polyamine. Where the mixture is a blend ofbackbone and chain extender polyamines the resulting elastomers may beviewed as polyureas. Where the mixture is a blend of backbone polyol andchain extender polyamines the resulting elastomers may be viewed asmixed polyureas-polyurethanes. However, it will be understood by thoseskilled in the art that the elastomers made according to the latter arecomplex chemical structures having both polyurethane and polyureasegments.

The nature and breadth of our invention may be summarized bycharacterizing the reactive components in the two streams as well astheir ratio of equivalents. The key for the following table is:

    ______________________________________                                        Component Variation in RIM Elastomer                                          Component    Case 1  Case 2    Case 3                                                                              Case 4                                   ______________________________________                                        I            x       x         x     x                                        B.sub.A      x       x                                                        B.sub.o                        x     x                                        D            x       x         x     x                                        E.sub.A and/or E.sub.o                                                                             x               x                                        ______________________________________                                         I = polyisocyanate;                                                           B.sub.A, B.sub.o = backbone polyamine and polyol, resp.;                      D = diamine of this invention;                                                E.sub.A, E.sub.o = chain extender polyamine and polyol, resp.            

The combination of specified components along with their ratios thenfully define this invention. Those ratios which are independentvariables, their verbal characterization, and their values for variantsof our invention follow. ##EQU1## is the ratio of equivalents ofisocyanate-reactive components in the second stream to thepolyisocyanate in the first stream. In all cases this ratio is between0.7 and 1.3, and more generally is between 0.85 and 1.05, and even morefrequently is between about 0.90 and about 1.0. ##EQU2## is the ratio ofequivalents of the diamines of this invention plus other chainextenders, if any, to the total isocyanate-reactive components of thesecond stream. In all cases r₂ is between 0.2 and 0.8, with thepreferred ratio being from about 0.3 to about 0.7. Stated differentlythe ratio varies around a central point where the number of equivalentsof the backbone polyamine or polyol is equal to that of the otherisocyanate-reactive components of the second stream.

In one variant E_(A), E_(o) =0, i.e., there are no chain extenders inthe second stream other than the diamines of this invention. Thiscorresponds to case 1 and case 3 resp.

In another variant the second stream contains a chain extender polyol inaddition to the other isocyanate-reactive components B_(A) (or B_(o))and D. This polyol is present to the extent of about 20 to about 100equivalents percent based on the diamines of this invention. Since thediamines of this invention have been designated as chain extenderpolyamines, the foregoing is equivalent to the statement that chainextender polyols constitute from about one-sixth to about one-half ofthe total chain extender mixture. That is, r₃, where ##EQU3## rangesbetween about 0.17 and about 0.50.

In the last variant to be discussed here the second stream contains asecond chain extender amine in addition to the other isocyanate reactivecomponents B_(A) (or B_(o)) and D. In this case the diamines of ourinvention are only a minor component, with the second chain extenderamine constituting 80-99 equivalents percent of the chain extendercomponents. Defining r₄ as, ##EQU4## this ratio of equivalents isbetween about 0.80 and about 0.99.

A broad variety of polyisocyanates may be used in the preparation of RIMelastomers and may be exemplified by such materials as the toluenediisocyanates, p- and m-phenylene diisocyanate, tetramethylenediisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexylenediisocyanate, 4,4'-methylenedicyclohexyl diisocyanate,4,4'-methylenediphenyl diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethanediisocyanate, 1,5-tetrahydronaphthalene diisocyanate, dianisidinediisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate,bis(2-methyl-3-isocyanatophenyl)methane,bis(3-methyl-4-isocyanatophenyl)methane, and 4,4'-diphenylpropanediisocyanate.

Also frequently used in RIM processing are methylene-bridged polyphenylpolyisocyanates such as are described and discussed in U.S. Pat. No.4,433,067, especially the polyisocyanates based on methylenediphenyldiisocyanate, especially the 4,4'-isomer and the uretonimine modifiedMDI as described therein. The term polyisocyanate also includes quasiprepolymers of polyisocyanates with active hydrogen containing materialswhere the polyisocyanate is typically reacted with from about 0.05 toabout 0.3 equivalents of a polyol. In principle a vast number ofpolyisocyanates are suitable for making RIM elastomers. However, inpractice polyisocyanates based on MDI are currently those principallyused in commerce.

If the diamines of this invention are used as the soleisocyanate-reactive component of the second stream the resultingelastomer is too brittle to be usable. Consequently, it is necessary tohave as another isocyanate-reactive component one which will provide asoft segment in the resulting elastomer. We here refer to suchcomponents as backbone polyamines and backbone polyols.

The backbone polyamines used in RIM are well known to those skilled inthe art but will be mentioned here, though not in great detail, andinclude diamines, triamines, and possibly higher polyfunctional amineswhich are primary amines. One class of such amines is related toaminodiphenylmethaneethers and esters of the formulae,

    H.sub.2 NC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NHC(O)--O--X--O--C(O)NHC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NH.sub.2,

    H.sub.2 NC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NHC(O)--O--X--C(O)O--C(O)NHC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NH.sub.2,

    H.sub.2 NC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NHC(O)--O--(O)C--X--C(O)O--C(O)NHC.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.4 NH.sub.2.

In these compounds X is usually an alkylene group, an alkyleneoxy group,or a poly(alkyleneoxy) group. A similar set of backbone polyamines usedin RIM results from substitution of both H₂ NC₆ H₄ CH₂ C₆ H₄ NHC(O)--groups by H₂ NC₆ H₃ (CH₃)NHC(O)-- moieties.

Another class of backbone polyamines have the formula H₂ N--Y--NH₂. Inone group Y is an alkylene chain. In a larger group Y is apoly(alkyleneoxy) or a polyester moiety with an alkylene group at bothterminii. So, for example, in this group are amine-capped polyols whichare the reaction product of a polyol and then an amine with alkyleneoxides as well as amine-capped hydroxyl-containing polyesters. Materialsof molecular weight in the 200-6000 range are most often utilized.

Tri- and higher polyamines of similar structure to that in the foregoingparagraph also may be utilized. For example, the reaction ofpentaerythritol with an alkylene oxide will give a polyether product,one terminus of which has the structural unit ##STR1## This can beamine-capped to give a triamine, and if the hydroxyl group at the otherterminus is so capped there will result a tetraamine. Both kinds ofproducts may be used as backbone polyamines.

The backbone polyols used in RIM are equally well known. The polyolsused are usually dihydric with trihydric and higher polyhydric polyolsused to a lesser degree. Examples of suitable polyols include ethyleneglycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4- and2,3-butylene glycol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol,cyclohexane dimethanol, 2-methyl-1,3-propanediol, glycerol,trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol,pentaerythritol, mannitol, sorbitol, diethylene glycol, triethyleneglycol, tetraethylene glycol, poly(ethylenoxy)glycols, generallydipropylene glycol, poly(propylenoxy)glycols, generally dibutyleneglycol, poly(butylenoxy)glycols generally, and the polymeric glycol fromcaprolactone, commonly known as polycaprolactone.

Other polyhydroxy materials of higher molecular weight arepolymerization products of epoxides, such as ethylene oxide, propyleneoxide, butylene oxide, styrene oxide, and epichlorohydrin, withmaterials having reactive hydrogen compounds, such as water and, moreparticularly, alcohols, including ethylene glycol, 1,3- and1,2-propylene glycol, trimethylolpropane, etc. Amino alcohols may bemade by condensing amino-containing compounds with the foregoingepoxides, using such materials such as ammonia, aniline, and ethylenediamine.

Hydroxyl-containing polyesters, polythioethers, polyacetals,polycarbonates, and polyester amides also may be used instead of ortogether with the foregoing polyols. Suitable polyesters include thereaction product of polyhydric alcohols and polybasic, preferablydibasic, carboxylic acids. The polyhydric alcohols which are often usedinclude the dihydric alcohols mentioned above. Examples of dicarboxylicacids include succinic acid, adipic acid, suberic acid, azelaic acid,sebacic acid, glutaric acid, phthalic acid, maleic acid, and fumaricacid. Hydroxyl-containing polythioethers, polyacetals, polycarbonates,and polyesteramides are less frequently employed in the preparation ofRIM elastomers. However, these are sufficiently well known to thosepracticing the art that they need not be further elaborated upon here.

The elastomer is made by reacting the polyisocyanate with a backbonepolyamine or polyol and at least one N,N'-disubstituted phenylenediamineof the structure, ##STR2## The para-phenylenediamines are somewhatfavored, although the use of metaphenylenediamines, and to a lesserextent the ortho-isomers, especially in mixtures with the para isomer,is relatively common.

The R groups are alkyl, alkenyl or aryl moieties-i.e., a monovalentradical whose parent is a linear or branched alkane, alkene, or aromatichydrocarbon, where each is independently selected from the groupconsisting of alkyl or alkenyl moieties containing from 1 up to about 20carbon atoms, and more preferably between 1 and about 10 carbon atoms,especially those having from 1 to 6 carbons. The alkyl or alkenyl groupmay be a primary, secondary, or tertiary group, although when it istertiary there is the risk that cure time may be too long to becommercially acceptable. Secondary alkyl or alkenyl groups arepreferred, and among these the secondary butyl group is particularlypreferred. Examples of alkyl groups which may be used in the practice ofthis invention include methyl, ethyl, propyl, butyl, pentyl, hexyl,heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl,pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosylmoieties. Examples of alkenyl groups are the unsaturated counterparts ofthe aforementioned alkyl groups. As stated previously, secondary alkylor alkenyl groups, i.e., those branched at the carbon atom bound to thenitrogen atom, and secondary alkyl groups in particular, are preferredin the practice of this invention. Representative of such groups are2-propyl, 2-butyl, 2-pentyl, 3-pentyl, 2-hexyl, 3-hexyl, and so forth.Representative aryl moieties include phenyl, tolyl, xylyl, and theirvarious isomers.

Cure time will depend not only on the type of alkyl groups on thediamine, but also will depend on the presence of other components if ablend of chain extending agents is used, as well as the nature of otherchain extenders in such a blend. For example, in general it will befound that cure times as a function of R increase in the order,

R=H<primary alkyl<secondary alkyl<tertiary alkyl.

In view of the foregoing it should be clear that the N,N'-disubstitutedphenylenediamines of this invention can be expected to manifest anenormous range of cure time in RIM. This variability presents distinctadvantages in permitting the end user to tailor the diamine to hisparticular needs. Since the properties of the resulting elastomer alsowill vary with the diamines of this invention, and since manyN,N'-dialkyl- or diarylphenylenediamines may be chosen with the samecure time, the end user generally also will have a broad choice of ourdiamines depending on the performance characteristics sought for thefinal product.

The alkylated diamines of this invention typically are prepared byconventional alkylation procedures performed on the precursor primaryamine. The second amino group may be at either the 2, 3, or 4 positionin the diamine. However, as previously noted, it is most desirable thatit be at the 4 position. A major advantage arises from the ease ofsynthesis of such materials, although it is not to be implied that thereare no differences in such materials as curing agents.

Defining an equivalent of polyamine or polyol as an amount whichfurnishes as many amino groups or hydroxyl groups, resp., as there areisocyanate groups in the first polyisocyanate stream, from about 0.70 toabout 1.3 equivalents total of the backbone polyamine or backbone polyoland our diamine are used in curing, with the range from about 0.85 toabout 1.05 more frequently used, and from about 0.90 to about 1.0 beingthe more usual one. Since each molecule of our diamine has 2 aminogroups, neither of which is tertiary, the diamines of this invention actas chain extenders and not as crosslinkers. As elaborated upon below thecuring mix may contain other materials, including otherisocyanate-reactive components such as chain extender polyols andpolyamines, in addition to, or partly replacing, the diamines of thisinvention, although the presence of such materials may not be necessaryto the success of this invention.

Catalysts may need to be used in some cases to decrease the reactiontime in order to obtain a mixture which sets sufficiently rapidly in themold to conform to the process requirements of RIM. Organic tincompounds are probably most frequently used and include such materialsas the tin(II) salts of carboxylic acids such as tin(II) acetate,tin(II) octoate, tin(II) ethylhexoate and tin(II) laurate, as well assuch materials as the dialkyl tin salts of carboxylic acids asexemplified by dibutyltindiacetate, dibutyltindilaurate,dibutyltinmaleate, and dioctyltindiacetate. Such tin salts may be usedeither alone or as a complex with amidines such as amino pyridines,amino pyrimidines, hydrazino pyridines, and tetrahydropyrimidines.

Catalysts based on metals such as lead, iron, mercury, cobalt andmanganese also have been used, and include compounds such as cobalt(III)acetylacetonate, cobalt naphthoate, manganese naphthoate, lead oleate,zinc naphthenate and zirconium naphthenate. Other catalysts which may beused include tertiary amines such as triethylamine, tributylamine,N-methylmorpholine, 1,4-diaza-bicyclo-(2,2,2)-octane,N-methyl-N'-dimethylaminoethylpiperazine, N,N-dimethylbenzylamine,N,N-dimethylcyclohexylamine, and 1,2-dimethylimidazole.

Other catalysts such as silaamines and basic nitrogen compounds such astetraalkyl ammonium hydroxide, alkali metal hydroxides such as sodiumhydroxide, and alkali metal alcoholates such as sodium methylate alsohave been used as catalysts. These catalysts are generally used in anamount from about 0.01 to about 10% by weight, preferably from about0.05 to about 1.0% by weight, based on the quantity of polyisocyanateand the quantity of materials reacting with the polyisocyanate.

The second stream also may contain materials such as blowing agents andsurfactants. Among suitable blowing agents are water and readilyvolatile organic substances or dissolved inert gases such as acetone,ethylacetate, methanol, ethanol, halogen substituted alkanes includingmethylene chloride, chloroform, vinylidene chloride,monofluorotrichloromethane, chlorodifluoromethane, anddichlorofluoromethane, butane, hexane, heptane, diethyl ether, nitrogen,air, carbon dioxide, etc. Examples of surfactants include the sodiumsalts of sulfonates or of fatty acids, amine salts of fatty acids,alkali metal or ammonium salts of sulfonic acids, polyether siloxanes,and the like. The second component also may contain pigments, dyes,flame retardants, stabilizers, plasticizers, fungicides andbactericides, and fillers.

As previously noted the blend of backbone polyamine or polyol and thechain extender amines of our invention may also contain one or morechain extender polyols or a second chain extender polyamine. The chainextender polyols used in this branch of our invention are polyhydricalcohols with more than two reactive hydroxyl groups per molecule, i.e.,more than two hydroxyl groups per molecule must react with the terminalisocyanate groups of the polyisocyanate. Normally this means the polyolsare at least trihydric, but since some trihydric alcohols may have oneor more hydroxyl groups unreactive under the reaction conditions ofcuring, it is not invariably true that a trihydric alcohol will suffice.In particular, phenolic hydroxyl moieties, and hydroxyl groups attachedto a tertiary carbon atom, usually will be unreactive in curingpolyisocyanates, whereas the hydroxyl moiety associated with primary andsecondary alcohols will be reactive. With the use of polyols having morethan two reactive hydroxyls per molecule it is clear that such materialsact as both cross-linkers and chain extenders, although for conveniencewe refer to such materials as chain extender polyols. Among the polyolswhich may be used are included 1,1,1-tri(hydroxymethyl)propane,otherwise known as 2,2-di(hydroxymethyl)-1-butanol,1,1,1-tri(hydroxymethyl)ethane,N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene diamine,2,4,6-tris(N-methyl-N-hydroxymethylaminomethyl)phenol,1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol, mannitol,sorbitol, triglycols, castor oils, triisopropanolamine, andN,N,N',N'-tetrakis(hydroxyethyl)ethylene diamine. Chain extender polyolscommonly are used at a level between about 20 and about 100 equivalentspercent based on the diamines of our invention subject to theconstraints on the ratios r₁ and r₂ ; vide supra.

Where the blend of backbone polyamine or polyol and the diamines of ourinvention contains a second chain extender polyamine, the lattergenerally is a diamine where both amino groups are primary amino groups,and even more frequently is an aromatic primary diamine. Such materialsinclude 1-methyl-3,5-diethyl-2,4-diaminobenzene,1-methyl-3,5-diethyl-2,6-diaminobenzene, toluene diamine,1,3,5-triethyl-2,6-diaminobenzene,3,3'-dichloro-4,4-diaminodiphenylmethane (MOCA) and the like. When usedin a blend with the diamines of this invention the second chain extenderpolyamine constitutes the major portion of the blend, viz., from about80 to about 99 equivalents percent of the mixture of the diamines ofthis invention and the second chain extender polyamine is the latter.

The process of reaction injection moldings has been described above andwill not be repeated here. Solidification of the reaction mixture afterinjection into the mold usually takes place so rapidly that the mold maybe opened within about 15-30 seconds to afford material with sufficientgreen strength to be handled. Post curing of the elastomer is optionaland will depend on the desired properties of the end product, thevarious components used, etc. Where post curing is desired it generallywill be performed in a range between about 100° C. and about 150° C. fora time between about 1 and about 24 hours.

EXAMPLES

Typical Rim Formulation. A typical RIM machine for polyurethane andpolyurea RIM may be employed without modification. In the A-side (or theisocyanate) reservoir of the RIM machine is added the isocyanate to beused: In this case, a low molecular weight MDI-ether prepolymer. In theB-side reservoir are added the polyol, the diamines of this invention,and any other co-cures or additives compatible with the polyol anddiamine. In polyurea RIM, the polyol would be replaced with a polyaminein order to form the backbone of the polyurea with the isocyanate. Boththe A- and B-sides are cycled through their respective heat exchangerswhere both are brought up to 70° C. Both sides are flowed to theirrespective metering pumps which are loaded for the shot. The ratio ofthe two (which determines the stoichiometry of the final polymer) andthe shot size have been predetermined. The pistons of the metering pumpsare engaged and the shot forced into the mixing head and through to themold which is attached to the mixing head and is heated to between 70°and 100° C. After about 30 to 60 seconds, the mold is opened, the partejected, the mold and the mixing head cleaned, and a new shot readied.The part may be post-cured from 30 minutes to 17 hours depending on thetype of polymer made and the components used. Several representativeformulations and RIM conditions are summarized below.

                                      TABLE 1                                     __________________________________________________________________________    Sample RIM Formulations using Representative Diamines (1)                     __________________________________________________________________________    Isocyanate                                                                              MDI, carbo-                                                                             Poly(MDI)                                                                              MDI Prepolm                                                diimide modified                                                                        F = 2.7 (3)                                                                            0.756 kg                                                   0.588 kg  0.723 kg 4.14 equiv.                                                4.14 equiv.                                                                             5.40 equiv.                                               Polyol    Polyether,                                                                              Polyether,                                                                             Polyether,                                       Backbone  Mol. Wt. 2900                                                                           Mol. Wt. 2000                                                                          Mol. Wt. 2900                                              F = 3     F = 2    F = 3                                                      2.000 kg  2.000 kg 2.000 kg                                                   2.07 equiv.                                                                             2.00 equiv.                                                                            2.07 equiv.                                      Diamine   (2)       (2)      (2)                                                        0.217 kg. 0.356 kg.                                                                              0.217 kg                                                   1.97 equiv.                                                                             3.23 equiv.                                                                            1.97 equiv.                                      Catalyst  DBTDL (4), 0.15%                                                                        DBTDL, 0.15%                                                                           DBTDL, 0.15%                                     Stream Temp.                                                                            70° C.                                                                           70° C.                                                                          70° C.                                    Mold Temp 70° C.                                                                           70° C.                                                                          70° C.                                    Post-cure Temp.                                                                         100° C.                                                                          85° C.                                                                          100° C.                                   Post-cure Time, h                                                                       1.0       1.0      1.0                                              __________________________________________________________________________     (1) Ratios of the reagents metered out reflect the masses listed in the       table.                                                                        (2) Diamine is N,N'--di(2butyl)-phenylenediamine. Equivalent weight is        110.2. Isocyanate index is 1.05 in all cases.                                 (3) F is the average number of reactive sites per molecule                    (4) Dibutyltin dilaurate                                                 

                                      TABLE 2                                     __________________________________________________________________________    Sample Polyurethane RIM Formulations using Diamines and                       a Chain Extender Polyamine (1).                                               __________________________________________________________________________    Isocyanate                                                                              MDI, carbodi-                                                                          MDI carbodi-                                                                           MDI Carbodi-                                                imide modified                                                                         imide modified                                                                         imide modified                                              0.569 kg 0.474 kg 0.474 kg                                                    4.00 equiv.                                                                            3.33 equiv.                                                                            3.33 equiv.                                       Polyol    Polyether,                                                                             Polyether,                                                                             Polyether,                                        Backbone  Mol. Wt. 2000                                                                          Mol. Wt. 3600                                                                          Mol. Wt. 3600                                               F = 2    F = 3    F = 3                                                       2.000 kg 2.000 kg 2.000 kg                                                    2.00 equiv.                                                                            1.67 equiv.                                                                            1.67 equiv.                                       Diamine   (2)      (2)      (2)                                                         0.042 kg.                                                                              0.009 kg.                                                                              0.009 kg                                                    0.38 equiv.                                                                            0.08 equiv.                                                                            0.08 equiv.                                                 (20%)    (5%)     (5%)                                              Chain extender                                                                          A (3)    A (3)    B (4)                                             Polyamine 0.135 kg 0.134 kg 0.161 kg                                                    1.52 equiv.                                                                            1.50 equiv.                                                                            1.50 equiv.                                                 (80%)    (95%)    (95%)                                             Catalyst  NONE     NONE     NONE                                              Stream Temp.                                                                            70° C.                                                                          70° C.                                                                          70° C.                                     Mold Temp 70° C.                                                                          70° C.                                                                          70° C.                                     Post-cure Temp.                                                                         100° C.                                                                         100° C.                                                                         100° C.                                    Post-cure Time, h                                                                       1.0      1.0      1.0                                               __________________________________________________________________________     (1) Ratios of the reagents metered out reflect the masses listed in the       table.                                                                        (2) Diamine is N,N'--di(2butyl)-phenylenediamine. Equivalent weight is        110.2. Isocyanate index is 1.05 in all cases.                                 (3) A = diethyltoluene diamine (DETDA)                                        (4) B = Ethacure 300, (Ethyl Corp.), an 80/20 isomeric mixture of             di(methylthio)2,4-toluene diamine and di(methylthio)2,6-toluene diamine  

                                      TABLE 3                                     __________________________________________________________________________    Sample Polyurethane and Polyurea RIM Formulations using                       Diamine (1).                                                                  __________________________________________________________________________    Isocyanate                                                                              MDI Prepolm                                                                            MDI Prepolm                                                                            MDI Prepolm                                                 0.833 kg 0.609 kg 0.438 kg                                                    4.56 equiv.                                                                            3.34 equiv.                                                                            2.40 equiv.                                       Polyol    Polyether,                                                                             Polyether,                                                                             --                                                Backbone  Mol. Wt. 2630                                                                          Mol. Wt. 3600                                                        F = 3 (3)                                                                              F = 3                                                                2.000 kg 2.000 kg                                                             2.28 equiv.                                                                            1.67 equiv.                                                Polyamine --       --       Polyoxyalkylene                                   Backbone                    amine                                                                         Mol. Wt. 5000                                                                 F = 3                                                                         2.000 kg                                                                      1.20 equiv.                                       Diamine   (2)      (2)      (2)                                                         0.239 kg.                                                                              0.174 kg.                                                                              0.126 kg                                                    2.17 equiv.                                                                            1.58 equiv.                                                                            1.14 equiv.                                       Catalyst  NONE     NONE     NONE                                              Stream Temp.                                                                            70° C.                                                                          70° C.                                                                          70° C.                                     Mold Temp 70° C.                                                                          70° C.                                                                          70° C.                                     Post-cure Temp.                                                                         100° C.                                                                         100° C.                                                                         100° C.                                    Post-cure Time, h                                                                       1.0      1.0      0.5                                               __________________________________________________________________________     (1) Ratios of the reagents metered out reflect the masses listed in the       table.                                                                        (2) Diamine is N,N'--di(2butyl)-phenylenediamine. Equivalent weight is        110.2. Isocyanate index is 1.05 in all cases.                                  (3) F is the average number of reactive sites per molecule.             

                                      TABLE 4                                     __________________________________________________________________________    Polyurea RIM Formulations using Diamines and                                  a Chain Extender Polyamine (1).                                               __________________________________________________________________________    Isocyanate                                                                             MDI, carbodi-                                                                           MDI prepolym.                                                                          MDI Prepolym                                               imide modified                                                                          0.438 kg 0.438 kg                                                   0.341 kg  2.40 equiv.                                                                            2.40 equiv.                                                2.39 equiv.                                                          Polyamine                                                                              Polyoxyalkylene                                                                         Polyoxyalkylene                                                                        Polyoxyalkylene                                   Backbone amine     amine    amine                                                      Mol. Wt. 5000                                                                           Mol. Wt. 5000                                                                          Mol. Wt. 5000                                              F = 3 (5) F = 3    F = 3                                                      2.000 kg  2.000 kg 2.000 kg                                                   1.20 equiv.                                                                             1.20 equiv.                                                                            1.20 equiv.                                       Diamine  (2)       (2)      (2)                                                        0.021 kg. 0.006 kg.                                                                              0.006 kg                                                   0.23 equiv.                                                                             0.06 equiv.                                                                            0.06 equiv.                                                (20%)     (5%)     (5%)                                              Chain extender                                                                         A (3)     A (3)    B (4)                                             Polyamine                                                                              0.081 kg  0.096 kg 0.116 kg                                                   0.91 equiv.                                                                             1.08 equiv.                                                                            1.08 equiv.                                                (80%)     (95%)    (95%)                                             Catalyst NONE      NONE     NONE                                              Stream Temp.                                                                           50° C.                                                                           50° C.                                                                          50° C.                                     Mold Temp                                                                              70° C.                                                                           70° C.                                                                          70° C.                                     Post-cure Temp.                                                                        100° C.                                                                          100° C.                                                                         100° C.                                    Post-cure Time, h                                                                      1.0       1.0      1.0                                               __________________________________________________________________________     (1) Ratios of the reagents metered out reflect the masses listed in the       table.                                                                        (2) Diamine is N,N'--di(2butyl)-phenylenediamine. Equivalent weight is        110.2. Isocyanate index is 1.05 in all cases.                                 (3) A = diethyltoluene diamine (DETDA)                                        (4) B = Ethacure 300, (Ethyl Corp.), an 80/20 isomeric mixture of             di(methylthio)2,4-toluene diamine and di(methylthio)2,6-toluene diamine       (5) F is the average number of reactive sites per molecule.              

                                      TABLE 5                                     __________________________________________________________________________    Sample Polyurea RIM Formulations using Diamines and                           a Second Chain Extender Polyamine (1).                                        __________________________________________________________________________    Isocyanate                                                                             MDI prepolym.                                                                           MDI prepolym.                                                                          MDI Prepolym                                               0.438 kg  0.438 kg 0.438 kg                                                   2.40 equiv.                                                                             2.40 equiv.                                                                            2.40 equiv.                                       Polyamine                                                                              Polyoxyalkylene                                                                         Polyoxyalkylene                                                                        Polyoxyalkylene                                   Backbone amine     amine    amine                                                      Mol. Wt. 5000                                                                           Mol. Wt. 5000                                                                          Mol. Wt. 5000                                              F = 3 (6) F = 3    F = 3                                                      2.000 kg  2.000 kg 2.000 kg                                                   1.20 equiv.                                                                             1.20 equiv.                                                                            1.20 equiv.                                       Diamine  (2)       (3)      (4)                                                        0.006 kg. 0.009 kg.                                                                              0.007 kg                                                   0.06 equiv.                                                                             0.06 equiv.                                                                            0.06 equiv.                                                (5%)      (5%)     (5%)                                              Chain extender                                                                         A (5)     A (5)    A (5)                                             Polyamine                                                                              0.096 kg  0.096 kg 0.096 kg                                                   1.08 equiv.                                                                             1.08 equiv.                                                                            1.08 equiv.                                                (95%)     (95%)    (95%)                                             Catalyst NONE      NONE     NONE                                              Stream Temp.                                                                           50° C.                                                                           50° C.                                                                          50° C.                                     Mold Temp                                                                              70° C.                                                                           70° C.                                                                          70° C.                                     Post-cure Temp.                                                                        100° C.                                                                          100° C.                                                                         100° C.                                    Post-cure Time, h                                                                      1.0       1.0      1.0                                               __________________________________________________________________________     (1) Ratios of the reagents metered out reflect the masses listed in the       table.                                                                        (2) Diamine is N,N'--di[3(5-methylheptyl)1,4phenylenediamine. Equivalent      weight is 166.3. Isocyanate index is 1.05 in all cases.                       (3) Diamine is N,N'--di(2butyl)-1,2-phenylenediamine. Equivalent weight i     110.2                                                                         (4) Diamine is N,N'--diphenyl1,4-phenylenediamine. Equivalent weight is       130.2.                                                                        (5) A = diethyltoluene diamine (DETDA)                                        (6) F is the average number of reactive sites per molecule.              

What is claimed is:
 1. A reaction injection molded elastomer made byreacting in a closed mold a first stream comprising one or morepolyisocyanates with a second stream comprising from about 0.7 to about1.3 equivalents of a blend of compounds having isocyanate reactivehydrogens said blend consisting essentially of a backbone polyamine(B_(A)) or a backbone polyol (B_(o)) and a chain extender diamine (D)which is at least one N,N'-disubstituted phenylenediamine of thestructure, ##STR3## where R₁ and R₂ are independently selected from thegroup consisting of monovalent alkyl or alkenyl moieties containing from1 to about 20 carbon atoms or a monovalent aryl moiety, and where thechain extender diamine constitutes from about 20 to about 80 equivalentspercent of the blend.
 2. The elastomer of claim 1 where the secondstream contains from 0.85 to 1.05 equivalents of isocyanate-reactivecomponents.
 3. The elastomer of claim 2 where the stream contains fromabout 0.90 to about 1.0 equivalents.
 4. The elastomer of claim 1 wherethe chain extender diamine constitutes from about 30 to about 70equivalents percent of the blend.
 5. The elastomer of claim 1 where thepolyisocyanate is toluene diisocyanate, methylenediphenyl diisocyanate,or a polymer of methylenediphenyl diisocyanate.
 6. The elastomer ofclaim 1 where at least one R is an aryl moiety containing from 6 to 10carbon atoms.
 7. The elastomer of claim 6 where the aryl moiety isphenyl.
 8. The elastomer of claim 1 where the alkyl or alkenyl moietycontains from 1 to about 10 carbon atoms.
 9. The elastomer of claim 8where the moiety contains from 1 to 6 carbon atoms.
 10. The elastomer ofclaim 1 where the moiety is an alkyl moiety.
 11. The elastomer of claim10 where the alkyl moiety is a secondary alkyl moiety.
 12. The elastomerof claim 11 where the alkyl moiety is isopropyl or sec-butyl.
 13. Theelastomer of claim 1 where the diamine is a paraphenylenediamine. 14.The elastomer of claim 1 where from about 20 to about 50% of the chainextender diamine is replaced by a like number of equivalents of a chainextender polyol.
 15. The elastomer of claim 14 where said polyol is1,1,1-tri(hydroxymethyl)propane,N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene diamine, or2,4,6-tris(N-methyl-N-hydroxymethylaminomethyl)phenol.